Readily inspectable and cleanable emergency valve for storage tank

ABSTRACT

An emergency valve assembly for a tank adapted to contain liquid such as for instance hazardous material, with the valve assembly including a valve head for closing the discharge port from the tank in an operative closed position of the valve head, and with a first operating unit coacting with the valve head for selectively opening the latter and a separate second operating unit coacting with the valve head for automatically closing the latter. The first operating unit has a portion adapted for accessibility from exteriorly of the tank and includes a fluid power connection to the first operating unit, for selectively supplying pressurized fluid to such operating unit; for causing opening of the valve head via such operating unit upon application of pressurized fluid thereto. The arrangement is such that the valve assembly including both operating units may be readily disassembled for cleaning and inspection and then reassembled with the tank, and with the valve assembly being structurally reliable for handling the liquid contents of the tank.

This invention relates to a novel and improved valve particularlyadapted for the control of liquid flow from a storage tank therefor,such as for instance a tank truck or trailer which may be used fortransport of flammable and/or hazardous materials, as well asnon-hazardous materials.

Valves of this general type are termed emergency valves and arecustomarily provided with means for preventing accidental orunintentional discharge of the liquid contents from the tank byproviding for maintaining the valve in a closed condition, andespecially in the event of accident or fire which may damage piping, orwhich may damage the tank structure, such as for instance in the eventof a traffic accident involving a tank truck or tank trailer.

There is substantial volume in this country and abroad of transportingliquids such as chemicals both hazardous and non-hazardous, andflammable and non-flammable, in tank trucks or trailers, or the like,and therefore it is necessary to have a valve structure which not onlyreliably controls the contents of the containing tank, but also one thatcan be thoroughly cleaned after each load is carried by the associatedtank, so as to avoid the possibility of load contamination. It isimportant therefore that any valve structure utilized with tank trucksor tank trailers, or the like, be susceptible to ready inspection,cleaning and associated expeditious disassembly and reassembly thereof.

Various arrangements of emergency valves have therefore evolved toattempt to alleviate the inspection and cleaning problems in connectionwith a tank or trailer truck, but none of such prior art valves are, toapplicants' knowledge, as readily disassembleable and readilyreassembleable as the present valve structure, which expedites theinspection and cleaning problems associated with valve structure of thistype.

BACKGROUND OF THE INVENTION

U.S. Pat. No. 3,065,949 dated Nov. 27, 1962 to Joseph H. DeFrees andentitled Chemical Emergency Valve, discloses a type of emergency valvewhich attempts to provide greater simplification in the cleaningoperation of the valve, with the latter being accomplished by presentinga valve structure wherein the working parts are enclosed, so as to beout of contact with the liquid being carried, charged or discharged fromthe tank.

Various other emergency type valves are known in the art, such as forinstance U.S. Pat. No. 3,910,551 in the name of Joseph H. DeFrees issuedAug. 23, 1977; Canadian patent No. 654,932 in the name of Joseph H.DeFrees and issued Jan. 1, 1963 and entitled Bottom Loading EmergencyValve; and Canadian patent No. 654,916 dated Jan. 1, 1963 and entitledChemical Emergency Valve. However, in all of these prior art valveassemblies, the disassembly, inspection and cleaning thereof representsquite a time consuming task and thus an undesirable situation in theoperation of inspecting and cleaning the valves between loads so as toattempt to prevent contamination between such loads.

SUMMARY OF THE INVENTION

Accordingly, an object of the present invention is to provide a novelemergency valve structure which provides greater simplification in theinspection and cleaning operations involved therewith.

A further object of the invention is to provide a valve of theaforementioned type which includes a spring actuated operating unit forurging the valve head of the valve into a closed condition with respectto the associated valve seat, and a pressurized fluid actuated operatingunit which is accessible from exteriorly of the associated tank, andoperative to cause selective opening of the valve head with respect tothe valve seat.

A still further object of the invention is to provide a valve of theaforedescribed type which includes means for providing for rapid andready disassembly and reassembly of the valve head with respect to thevalve seat from interiorly of the tank, and likewise providing for readydisassembly and reassembly of the fluid pressure valve operating meansor operating unit from exteriorly of such operating unit and exteriorlyof the associated tank, for inspection, cleaning and/or repairingthereof.

A still further object of the invention is to provide a valve of theaforementioned type which includes auxiliary means adapted formechanical coaction with the fluid pressure operating unit, for manuallyactuating such operating unit to cause opening of the valve, without thenecessity of applying pressurized fluid to such operating unit foractuation of the same.

Another object of the invention is to provide a valve of theaforementioned type wherein the spring actuated operating unit for thevalve includes a spider member coacting with headed post members, andproviding for urging of the valve head toward closed condition on thevalve seat, and wherein the valve head can be disassembled from coactionwith the valve seat by rotation of the spider member and associatedspring operating unit relative to the headed posts and in a generallyhorizontal plane, so as to provide for expeditious inspection, cleaningand/or repairing thereof.

A still further object of the invention is to provide a valve of theaforementioned type wherein an operating unit for closing the valve headand the associated valve head, can be readily disassembled from coactionwith the valve seat of the valve, from interiorly of the associatedtank, and wherein a further separate operating unit for the valve head,for opening the latter, can be disassembled from exteriorly of the tankand exteriorly of the valve head, for ready and expeditious inspection,cleaning and/or repair thereof.

Other objects and advantages of the invention will be apparent from thefollowing description taken in conjunction with the accompanyingdrawings wherein

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectioned, elevational view of an emergency valve embodyingthe invention; at the bottom portion of FIG. 1 there is shown anassociated mechanical nut means which is adapted from manually actuatingthe pressurized fluid operating unit of the valve, to cause opening ofthe valve head without the necessity of applying pressurized fluid tosuch pressurized fluid operating unit; the phantom lines represent atank in which the valve is mounted;

FIG. 2 is a top-plan view of the valve illustrated in FIG. 1, showingthe spring actuated operating unit for the valve head which includes anassociated spider member, facilitating ready removal of the operatingunit and valve head from coaction with the valve seat for inspection,cleaning and/or repair thereof, and providing for ready reassembly withthe valve seat after such inspection, cleaning and/or repair;

FIG. 3 is a top plan view of the spider member and attached springoperating unit illustrated in FIG. 2, but separated from the headed poststructure of the FIG. 2 valve seat illustration;

FIG. 4 is a side elevational broken view of the spider member andassociated operating unit(shown in phantom lines) taken from the righthand side of FIG. 3;

FIG. 5 is an enlarged top plan view of the flange member adapted for usein coupling the fluid pressure operating unit of the valve to a sourceof pressurized fluid, and which upon removal from the remainder of thefluid pressure operating unit enables ready disassembly of the interiormechanism of such operating unit, for inspection, cleaning and/or repairthereof;

FIG. 6 is an elevational sectional view of the subassembly (shown inFIG. 1) of the valve seat and associated post structure, the liquidconveying elbow, and the housing only of the fluid pressure operatingunit, such housing being secured to the elbow and projecting interiorlyand exteriorly thereof;

FIG. 7 is an enlarged, bottom plan view taken generally along the planeof line 7-7 of FIG. 6, looking in the direction of the arrows;

FIG. 8 is an elevational view of the piston stem of the piston unit ofthe fluid pressure operating unit, for the valve;

FIG. 9 is an enlarged, front elevational view of the hanger tie(illustrated in FIG. 1) for temporarily supporting the flange member(FIG. 5) of the fluid pressure operating unit on the housing thereofprior to the attachment of the threaded fastener means securing theflange member to the remainder of the fluid pressure operating unit; and

FIG. 10 is a side elevational view of the FIG. 9 hanger tie, taken fromthe left hand side thereof.

DESCRIPTION OF PREFERRED EMBODIMENT

Referring now again to the drawings, and in particular to FIG. 1thereof, there is shown, in phantom, a fragmentary portion 10 of thebottom wall of a liquid transportation tank, having an aperture 12formed therein to the periphery of which is attached a valve seat 14,and as by means of threaded fasteners 16, passing through apertures inthe tank 10 and aligned apertures 18 in the valve seat. A leak-proofgasket 20 is preferably provided between the seat 14 and the undersideof tank 10. Seat 14 in the embodiment illustrated, supports a conduitelbow 22 thereon through which liquid may be discharged from and alsodirected into the tank, with the elbow having at its distal end aconnection flange 22a adapted for attachment to other liquid carryingpiping (not shown) conventionally associated with a liquid transportingtank 10. Shear groove 22b is preferably provided in elbow 22.

A valve assembly 23 which includes the aforementioned seat 14 and acoacting valve head member 24, is provided for closing the port 26 inthe valve seat, with the head 24 preferably having a sealing means,(e.g. gasket or 0-ring) 24a associated therewith, for preventing leakagebetween the valve head 24 and the port 26 when the valve is in the fullline closed condition, as illustrated for instance in FIG. 1.

In the embodiment illustrated, the valve head 24 includes a stem portion28 secured thereto and extending both upwardly and downwardly from theseat closing area, for a purpose to be hereinafter discussed.

The valve seat 14 also includes in the embodiment illustrated, aplurality of headed post members 30, secured as by welds 30a to thevalve seat, and projecting upwardly therefrom as illustrated in FIGS. 1and 2.

A spring actuated operating unit 32 coacts with the valve head 24, toautomatically normally urge the valve head 24 to a closed position withrespect to port 26, and as illustrated in FIG. 1.

Operating unit 32 includes a housing 34 defining a closed chamber 34a,closed at its lower end by a preferably removable closure member 36secured to housing 34 by retaining ring 36a, and which may also includesealing means 36 coacting between member 36, and the interior of thehousing 34, for sealing the interior of the housing against ingress ofliquid carried or transported in the tank 10.

As can be best seen from FIG. 1, the aforementioned stem 28 of the valvehead 24 movably extends upwardly through the closure member 36, and intothe housing chamber 34a and has on its upper end a shoulder 38,supporting a spring washer 40 and between which and the interior upperend of the housing 34, extends a coil spring 42, with the coil spring 42being under predetermined compression so as to urge the stem 38 andassociated valve head 24 downwardly toward a closed position withrespect to port 26.

In accordance with the invention, the operating unit 32 includes aspider member 44 (FIGS. 1, 2, 3, and 4) which may be detachablyconnected by means of threaded fasteners 46 to the housing closure 36,with spider 44 including outwardly projecting arms 44a, which at theirdistal ends include claw portions 44b, with claw portions 44b beingadapted to detachably coact with the aforementioned headed posts 30, fordetachably holding the operating unit 32 in operative position on theheaded posts of the valve seat 14, and thus hold the valve head 24 inits normally closed condition with respect to the port 26 in the valveseat 14.

It will be seen that by applying a downward vertical force to theoperating unit 32, and then twisting the operating unit 32 including theassociated spider 44 in a generally horizontal plane, the claw portions44b can be readily detached from the headed posts 30, to permit removalof the operating unit 32 and associated valve head 24 from the valveseat for ready inspection, cleaning or repairing of the operating unit32 and/or the valve seat and valve head members. Sealing means 48coacting between the upper section of stem 28 and the central portion ofspider 44 normally prevents leakage of liquid in the tank from enteringthe closed chamber 34a of operating unit 32. Thus it will be understoodthat the spring operating unit 32 including spider 44 can be readilyseparated from the valve seat 14 and from interiorly of the tank 10, forexpeditious inspection and cleaning of the valve structure disposedwithin the tank.

A further pressurized fluid operating unit 50, which includes a meansfor applying pressurized fluid thereto for actuating the operating unit,is provided on the conduit or elbow 22 and is for the purpose ofoperating the valve head 24 from a remote location so as to open thevalve head and permit for instance the discharge of the liquid contentsin the tank 10, and to open the valve head, from the full line closedposition illustrated in FIG. 1 to for instance the phantom line openposition illustrated in FIG. 1, to permit discharge of the liquidcontents in the tank, or to permit bottom loading of the tank in theconventional well-known manner.

Pressurized fluid actuated operating member 50 comprises a housing 52,which extends through the wall of duct 22 interiorly and exteriorlythereof and is secured to such wall in fluid sealed relationship, as bymeans of welds 52a.

Operating unit 50 includes a barrel member 54 disposed interiorly ofhousing 52, which includes in its upper end a barrel cap 56 preferablythreaded thereto as at 56a, and with a shaft member 58 disposed in thebarrel 54 and projecting upwardly therefrom and adapted for engagementwith the underside of the lower portion of stem 28 attached to valvehead 24.

It will be understood that shaft 58 is completely separate from stem 28,and upon disassembly of operating unit 50, as will be hereinafterdescribed, the shaft 58 is pulled downwardly out of the barrel inhousing 52.

A base member 60 may be provided in encircling relationship to shaft 58with the base member being secured to the barrel 54 as by means ofthreaded set screws 62 which extend into a groove 64 encircling base 60,and a spring 66 may extend between the base unit 60 and a packing orsealing means 68 for sealing the shaft 58 in its axial movement withrespect to the barrel 54 and associated housing 52.

0-ring carrier 70 may be positioned on the top of packing 68 between thebarrel cap 56 and the shaft 58, and packing 72 may be likewise providedcoacting with the upper end of the barrel cap for preventing the leakageof liquid contents in the tank 10 from seeping into the operating unit50.

Disposed below the shaft 58 in barrel 54 is a piston unit 74 comprisingpiston head assembly 74a which is detachably connected to piston stem74b, the latter extending downwardly from the bottom of the barrel 54through the housing flange portion 76, secured as by means of welds, tothe lower end of housing 52, and through the pressurized fluid inletflange 78 which is secured as by means of threaded nut and boltfasteners 80 to the aforementioned housing flange portion 76. The lowerend of piston stem 74b can be threaded as at 82 (FIG. 1 and 8) and inthe embodiment illustrated is shown as receiving in threaded coactiontherewith an indicator rod 84, which enables visual indication of theposition of the piston unit 74 in barrel 54 and with respect to theshaft 58.

Aforementioned inlet flange 78, in the embodiment illustrated, includesa central boss 78a (FIG. 5) which includes circumferential recess 78btherein receiving a sealing means such as an 0-ring 86 (FIG. 1) forsealing the inlet flange with respect to the associated barrel member54. A pressurized fluid inlet port 88 is provided in inlet flange 78,which is adapted for connection as by means of a fluid pressure line(not shown) to a remote source of pressurized fluid, for applyingpressurized fluid to the inlet flange 78 and thence through passageway90 therein to a pressure chamber 92 in barrel 54, for actuating pistonunit 74 and moving it upwardly in the barrel 54 against the shaft 58,thus causing upward movement of the shaft 58 and resultant movement ofthe valve head 24 from the closed position illustrated to an openposition, such as for instance the phantom line position illustrated inFIG. 1.

Fluid pressure chamber 92 communicates with the passageway 94 in inletflange 78 and may be provided with a ball type relief valve 95 thereinwhich may be manually actuated both to open and closed conditions, forselectively bleeding the fluid pressure chamber upon application offluid pressure to the entry port 88 to clear the pressure chamber 92 ofair. It should be understood that by threading the actuator 96 of therelief valve 95 into or from its receiving cavity, the ball of thepressure relief valve 95 can be either disposed so as to close thepassageway 94 or to open it for relief of fluid pressure in chamber 92.

Circumscribing the piston stem 74b and received in a socket on theunderside of the inlet flange member 78, as by threading is an indicatorguide member 98. A U-seal 98a can be provided coating between theindicator guide, the piston stem 74b and the inlet flange 78, forpreventing leakage of pressurized fluid applied to the pressure chamber92 via pressurized fluid inlet port 88.

Indicator guide 98 is preferably threaded on its exterior, asillustrated in FIG. 1, and is provided with a wiper scraper 100 and awiper scraper nut 100a coacting with the indicator guide 98 in threadedrelationship, and as shown in FIG. 1. The aforementioned indicator rod84 projects downwardly from scraper 100 and associated nut 100a.

In order to be able to manually actuate the piston unit 74 to causeupward movement of the shaft 58, and thus opening of the valve head 24,in the event of failure of actuating pressure at port 88, there ispreferably provided a screw jack nut 102, which is threaded as 102a onits interior and which is provided with an abutment 102b at the lowerend thereof so that if a manual actuation of the piston unit 74 isdesired, the wiper scraper nut 100a and associated wiper scraper 100,can be detached from the indicator guide 98 by unthreading thereof, andthen the screw jack nut 102 can be threaded onto the threaded exteriorof the indicator guide, with the indicator rod 84 being received in thejack nut 102 until the lower end of the indicator rod 84 engages theabutment 102b in the jack nut, whereupon further threading of the jacknut onto the indicator guide will cause mechanical lifting of theindicator rod and attached piston stem 74b, and thus actuation of thepiston unit 74 to cause upward movement of shaft 58 which then appliespressure to the downwardly depending valve head stem 28, and thus causelifting of the valve head 24 from seat 14 to open the port 26 in theseat member, and against the resistance to compression of spring 42 ofoperating unit 32.

Reverse rotation of the jack nut 102 will, of course, permit the spring42 of operating unit 32, to return the valve head 24 to its normallyclosed position with respect to the discharge port 26 in the valve seat14.

It will be seen that by removal of the threaded fasteners 80 extendingthrough the receiving openings 104 in the inlet flange member 78 and inthe aligned openings 104a in the end flange portion 76 of the associatedhousing member 52, the inlet flange member 78 can be dropped downwardlyaway from coaction with the housing flange, and resulting in exposure ofthe piston unit 74 and barrel 54 and ready removal of the piston unit 74and barrel member 54 from the interior of housing 52, together with theremoval of the shaft 58, for ready inspection, cleaning and/or repair ofthe operating unit 50. It will be seen that once the inlet flange 78 isremoved and the barrel and piston unit and shaft 58 are removed, theonly part of operating unit 50 still attached to the elbow 22 is thehousing 52 which is secured by welds thereto, but which can be readilycleaned in the event that any of the liquid that has passed through theelbow 22 from or to the tank, has seeped into the operating unit 50.

Referring now to FIGS. 9 and 10, in conjunction with FIG. 1, it will beseen that there is preferably provided in the operating unit 50, ahanger means 106, which extends downwardly from the aforementionedthreaded set screw 62 attaching the base 60 to the barrel 54 to beconnected or coupled to the inlet flange 78, for holding the inletflange suspended on the barrel 54 and thus on the operating unit 50,even when the fasteners 80 are removed, at which time the inlet flange78 can be pulled or forced downwardly away from the underside of theoperating unit 50.

In this connection, the hanger member 106 includes an opening 108therein , through which is received one of the set screw members 62aforementioned to secure the hanger 106 to the base 60, and a reducedsize leg portion 110 which is adapted to be received through an opening112 (FIG. 5) in the inlet flange 78, so as to permit the leg portion 110to pass through the inlet flange 78 and be bent beneath flange 78 tohold the inlet flange suspended from the barrel 54 via the hanger 106,even though the fasteners 80 have been removed. This, of course,facilitates not only the removal of the inlet flange 78 from itsfastened coaction with the housing flange portion 76 but alsofacilitates the reassembly of the inlet flange to the housing flangeafter the inspection and/or cleaning or repairing of the operating unit50 has been accomplished.

From the foregoing description and accompanying drawings it will be seenthat the invention provides a novel emergency valve assembly for a tankadapted to contain liquid contents, such as for instance, hazardousmaterials, with the valve assembly including a valve head for closing adischarge port from the tank in an operative closed position of thevalve head and including a first operating unit coacting with the valvehead for opening the latter, and a second operating unit coacting withthe valve head for automatically closing the latter. The valve assemblyprovides for expeditious inspection, repair and/or cleaning of the valveassembly by having both operating units readily disassembleable fromcoaction with the valve head, and after inspection, cleaning and/orrepair thereof, such operating units can be readily reassembled with thevalve head for again controlling the flow of liquid from the tank.

One of the operating units for the valve head is a spring operatedoperating unit for automatically urging the valve head toward closedposition while the other operating unit for the valve head is apressurized fluid operating unit which enables opening of the valve headfrom a location remote therefrom. Means is provided for mechanically ormanually actuating the pressurized fluid operated operating unit in theevent of failure of the pressurized fluid system, and means are alsoprovided on the valve assembly for visually indicating the position ofthe piston unit of the pressurized fluid actuated operating unit, so asto provide for visual indication of an existing position of the pistonunit of the operating unit.

The terms and expressions which have been used are used as terms ofdescription and not of limitation, and there is no intention in the useof such terms and expressions of excluding any equivalent of any of thefeatures shown or described, or portions thereof, and it is recognizedthat various modifications are possible within the scope of theinvention claimed.

We claim:
 1. An emergency valve for a tank adapted to contain liquid,said valve being adapted for assembly with the tank for enablingselective control of the discharge of liquid contents from the tank,said valve including a valve head and a coacting seat for closing adischarge port from the tank when said head is in operative closedposition with respect to said seat, and a generally vertically orientedoperating unit generally aligned with said seat and being totallyseparate from said head but coacting with said head from below thelatter in non-attached relationship for operating said head to move itfrom a closed position to an open position, said operating unitincluding an upwardly operable fluid powered piston unit, and alsohaving a downwardly projecting portion providing accessibility to saidoperating unit from exteriorly of the tank, and also including means onsaid portion for coupling said operation unit to a source of liquidpower, the latter being adapted for causing selective fluid poweredactuation of said piston unit of said operating unit and thus opening ofsaid valve head from a remote location with respect to said valve head,the first mentioned means including means providing for readydisassembly and reassembly of the first mentioned means from and to theremainder of said operating unit whereby said operation unit includingsaid piston unit can be readily separated from said head anddisassembled downwardly from exteriorly of said operating unit whenmounted on an associated tank, for inspection, cleaning and/or repairingof said operating unit, and other means coacting with said valve headand said valve seat from above the latter, and providing for rapid andready disassembly and reassembly of said valve head with respect to saidvalve seat, whereby said valve can be readily disassembled forinspection, cleaning and/or repair and then can be readily reassembledfor use.
 2. A valve in accordance with claim 1 wherein said seatincludes an elbow extending therefrom and communicating with said seat,said operating unit being mounted on said elbow and extending bothinteriorly into and exteriorly from said elbow in generally verticalalignment with said seat, the first mentioned means being on saidportion of said operating unit, which extends exteriorly from saidelbow.
 3. A valve in accordance with claim 1 including means adapted formechanical coaction with said operating unit for manually actuating thelatter to cause opening of said valve, without the necessity of applyingpressurized fluid to said operating unit for actuation of the same.
 4. Avalve in accordance with claim 1 wherein said operating unit includes ahousing extending into an associated discharge duct adapted for couplingto the tank in communication with the discharge port of the tank, withsaid housing extending through the defining wall of said discharge ductin fluid tight relationship and also extending from the exterior of saidduct, and wherein said first mentioned means is attached to said housingexteriorly of said duct for ready accessibility thereto.
 5. A valve inaccordance with claim 2 wherein said operating unit includes a housingand a barrel disposed within said housing, a shaft disposed within saidbarrel and projecting therefrom and upwardly from said housing, saidshaft ring separate from said valve head but being adapted forengagement with said valve head for opening the latter upon saidactuation of said operating unit, means sealing said shaft with respectto said barrel while permitting axial movement of said shaft relative tosaid barrel, said piston unit disposed within said barrel and beingadapted for communication with the first mentioned means for poweractuation of said operating unit, so that upon application ofpressurized fluid to said piston unit, said piston unit will causeupward outward movement of said shaft relative to said barrel andengagement of said shaft with said valve head, and thus cause opening ofsaid valve head.
 6. A valve in accordance with claim 5 wherein saidpiston unit includes a piston stem projecting outwardly of said barreland through said coupling means, and manual actuating means exteriorlyaccessible relative to said coupling means, for mechanically applyingpressure to said piston stem upon actuation of said manual actuatingmeans, for activating said piston unit by mechanical force and thuscausing said opening of said valve head.
 7. A valve in accordance withclaim 6 wherein said manual actuating means comprises a threaded studportion coupled to said operating unit in generally encompassingrelation to said piston stem, and a deep depth nut adapted for threadedcoaction with said threaded stud portion, said nut having means thereonadapted for engagement with the distal projecting end of said pistonstem and upon threading of said nut on said threaded stud portion,causing forced inward movement of said piston stem relative to saidbarrel and thus causing actuation of said piston unit and associatedoutward movement of said shaft relative to said barrel, for engagementwith said valve head to cause said opening of the latter.
 8. A valve inaccordance with claim 7 including sealing means coacting with saidpiston stem for preventing leakage from said operating unit, ofpressurized fluid applied to said operating unit for activating thelatter.
 9. A valve in accordance with claim 7 wherein said meansproviding for ready disassembly and reassembly of said first mentionedmeans from and to the remainder of said operating unit comprisesthreaded fasteners and wherein said barrel is completely open at thebottom thereof for withdrawal movement of said piston unit from saidbarrel upon disassembly of said coupling means from said operating unit,for cleaning and/or repairing said operating unit, said barrel beingremovable through the open bottom end of said housing upon disassemblyof said first mentioned means from said housing.
 10. A valve inaccordance with claim 5 including a base in said barrel encircling saidshift, a spring coacting between said base and said sealing mean foraiding in maintaining sealing of the shaft with respect to said housingand said barrel, while permitting lengthwise movement of said shaftrelative to said housing and said barrel, and means coacting betweensaid base and said barrel for detachedly locking said base inpredetermined position relative to said barrel.
 11. A valve inaccordance with claim 10 including hanger means coacting between saidlocking means and said coupling means for suspending said coupling meanson said housing and said barrel prior to application of fastener meansto said coupling means to detachably secure the latter to said housing,said fastener means comprising said means providing for readydisassembly and reassembly of the first mentioned means from and to theremainder of said operating unit.
 12. A valve in accordance with claim 6wherein said first mentioned means comprises a flange member having anentry portion therein for coupling to an associated source ofpressurized fluid with said flange member including a projectingembossment thereon adapted to be received within the interior of saidbarrel at a bottom end thereof in locating relation, sealing meanscoacting between said embossment and the interior surface of said barrelfor sealing the flange member relative to the interior of said barrel,and said means providing for ready disassembly and reassembly of thefirst mentioned means comprising fasteners and complementary receivingopenings on said flange member coacting between said housing and saidflange member and detachably securing said first mentioned means to saidhousing.
 13. A valve in accordance with claim 12 including reliefpassageway means in said flange member coacting with a pressure chamberin the lower end portion of said barrel and including a relief valve insaid passageway means adapted for manual actuation, for selectivelybleeding the fluid pressure chamber upon initial application ofpressurized fluid to said chamber via said entry port.
 14. A valve inaccordance with claim 1 wherein said other means includes means coactingwith said seat and adapted for positioning in the interior of anassociated tank, for detachably coupling said valve head in the tank toand from said seat for inspection, and cleaning of the valve.
 15. Avalve in accordance with claim 14 including a spring operating unitcoacting with said valve head, the last mentioned operating unitcomprising a housing and a spring coacting between the housing and thevalve head for urging the valve head toward said closed position on saidseat.
 16. A valve in accordance with claim 14 wherein the last mentionedmeans includes a further valve operating unit comprising a housingcontaining a spring and a spider portion disposed in sealed relation tothe lower end of said housing and coacting with headed posts extendingupwardly about said seat and detachably coupling said valve head to saidseat.
 17. A valve in accordance with claim 16 wherein said spiderportion has distal claw portions, said claw portions being adapted toreleasably coact with said headed posts projecting upwardly from saidvalve seat, said spider portion being spring loaded by said furtheroperating unit and so as to urge said valve head toward said valve seatbut providing for rotative movement of said further operating unitincluding said spider portion with respect to said headed posts in agenerally horizontal plane, so as to detach said further operating unitincluding said spider portion from coaction with said headed posts, andthus permit disassembly of said valve head from coaction with said valveseat.
 18. A valve in accordance with claim 17 wherein said valve headcoacting with said valve seat for closing the discharge opening in thetank has a stem portion projecting downwardly therefrom adapted forengagement with the first mentioned operating unit for causing openingof said valve head upon application of pressurized operating fluid tosaid first mentioned operating unit, and wherein said valve seatincludes means for detachably coupling said valve seat and associatedheaded posts to an associated tank.
 19. An emergency valve for a tankadapted to contain liquid, said valve being adapted for assembly withthe tank for enabling selective control of the discharge of liquidcontents from the tank, said valve including a valve head and a coactingseat for closing a discharge port from the tank when said head is inoperative closed position with respect to said seat, and an operatingunit generally aligned with said seat from below the latter and beingtotally separate from said head but coacting with said head in anon-attached relationship for operating said head to move it from aclosed position to an open position, said operating unit having aportion thereof providing accessibility from exteriorly of the tank andincluding means on said portion for coupling said operating unit to asource of fluid power, the latter being adapted for causing selectiveactuation of said operating unit and thus opening of said valve headfrom a remote location with respect to said valve head, the firstmentioned means including means providing for ready disassembly andreassembly of said first mentioned means from and to the remainder ofsaid operating unit whereby said operating unit can be readily separatedfrom said head and disassembled from exteriorly of said operating unitwhen mounted on an associated tank, for inspection, cleaning and/orrepairing of said operating unit upon disassembly of said firstmentioned means, said operating unit including a housing and a barreldisposed within said housing, a shaft disposed within said barrel andprojecting upwardly therefrom and from said housing, said shaft beingseparate from said valve head but being adapted for engagement with saidvalve head for opening the latter upon said actuation of said operatingunit, means sealing said shaft with respect to said barrel whilepermitting axial movement of said shaft relative to said barrel, and apiston unit disposed within said barrel and adapted for communicationwith the first mentioned means for power actuation of said operatingunit so that upon application of pressurized fluid to said piston unit,said piston unit will cause outward movement of said shaft relative tosaid barrel and engagement thereof with said valve head and thus causeopening of said valve head and including means for visually indicatingfrom exteriorly of said operating unit the position of said piston unitin said barrel and with respect to said shaft.
 20. An emergency valvefor a tank adapted to contain liquid, said valve being adapted forassembly with the tank for enabling selective control of the dischargeof liquid contents from the tank, said valve including a valve head andcoacting seat for closing a discharge port from the tank when said headis in operative closed position with respect to said seat, and anoperating unit generally aligned with said seat from below the latterand being totally separate from said head but coacting with said head innon-attached relationship for operating said head to move it from aclosed position to an open position, said operating unit having aportion thereof providing accessibility thereto from exteriorly of thetank and including means on said portion for coupling said operatingunit to a source of fluid power, the latter being adapted for causingselective actuation of said operating unit and thus opening of saidvalve head from a remote location with respect to said valve head, andmeans providing for rapid and ready disassembly and reassembly of saidvalve had with respect to said valve seat, whereby said valve can bereadily disassembled for inspection, cleaning and/or repair and then canbe readily reassembled for use, the last mentioned means including meanscoacting with said valve head and said seat and adapted for positioningin the interior of an associated tank for detachably coupling said valvehead in the tank to and from said seat for inspection and cleaning ofthe valve, and including a spring operating unit coacting with saidvalve head, the last mentioned operating unit being disposed above saidvalve head and comprising a housing and a spring in said housingcoacting between said housing and said valve head, for urging sid valvehead towrd said closed position on said seat, said last mentionedoperating unit also including a removable spider coupling meanssealingly disposed in the lower end of said housing and coacting inholding relation with headed post members projecting upwardly relativeto said seat, and said last mentioned operating unit and spider couplingmeans being rotatably releasable from said post members for providingeasy accessibility to said valve head within the tank.
 21. A valve inaccordance with claim 20 wherein said valve head includes an upwardlyprojecting stem, said spring coacting between said housing and saidstem, to urge said valve head toward said closed position, said lastmentioned operating unit including a removable lower closure member forsaid housing, said closure member proving for lengthwise movement ofsaid valve head stem therethrough and into said coaction with saidspring, sealing means coacting between said stem and said closure memberfor sealing the interior of said housing of said last mentionedoperating unit relative to the axially movable head stem, and meansdetachably coupling said spider coupling means to said closure member.22. A valve in accordance with claim 21 wherein said valve head steminclude a shoulder on the upper end thereof, a spring washer positionedon said shoulder, and said spring coacting between said spring washerand the interior of the top wall of said housing so as to urge saidvalve head stem and associated valve head downwardly into said closedposition relative to said valve seat.